1. Field of the Invention
This invention relates to the preparation of polyamideimides and is particularly concerned with polyamideimides derived from 1,1-cycloaliphatic bis(phenylamine) compounds or the corresponding diisocyanates.
2. Description of the Prior Art
Polyamideimide polymers and particularly aromatic polyamideimides derived from trimellitic anhydride or its derivatives and various aromatic diamines (or corresponding diisocyanates) are well recognized in the polymer art as highly useful materials in such applications as wire coating, films, molded articles and the like.
U.S. Pat. No. 3,696,077 typically discloses a series of polyamideimides based on the trimellitic anhydride residue and the residue of at least one member of a particular class of aromatic diamines. The polymers obtained are characterized as soluble in phenolic solvents; however, they are not characterized as fusible to the extent that they are melt processable.
U.S. Pat. No. 3,748,304 discloses copolyamideimides which may be injection molded but which call for a mixture of aromatic diamines to be used. U.S. Pat. No. 3,803,100 discloses phenolic solvent soluble but infusible polyamideimides.
British Pat. No. 1,168,978 discloses soluble but infusible polyamideimides prepared, illustratively, from trimellitic anhydride and certain diisocyanates inclusive of aromatic diisocyanates. Soluble and fusible polyamideimides are disclosed where the diisocyanate employed is aliphatic.
The polyamideimides prepared in accordance with the present invention are aromatic polyamideimides which are characterized by having good solvent solubility and by being fusible and melt processable without the necessity of introducing comonomers into the polymer chain, i.e., without resorting to the formation of copolyamideimides.
Additionally, the polyamideimides of the present invention exhibit a high degree of resistance to oxidative degradation and this property, in conjunction with those already noted, serves to distinguish them over the polyamideimides of the prior art.